1. Field of the Invention
The invention relates to a deposition system and associated apparatus and more particularly to a sealing apparatus for a driving shaft of a deposition system, an apparatus to reduce the weight of an effusion cell in a deposition system for ease of movement, and an apparatus to prevent a collision between effusion cells in a deposition system.
2. Description of the Related Art
Electroluminescent displays may be classified as inorganic electroluminescent displays or organic electroluminescent displays depending on the materials used for the luminescent layers. Organic electroluminescent displays are particularly advantageous because they are operable at a low voltage, have a lightweight and thin profile, a wide viewing angle, and a rapid response rate.
Organic electroluminescent devices may include an anode, an organic layer and a cathode formed in a stack on a substrate. The organic layer may include an organic luminescent layer, which emits light. An electron injection layer (EIL) and an electron transport layer (ETL) may be interposed between the cathode and the organic luminescent layer, and a hole injection layer (HIL) and an hole transport layer (HTL) may be interposed between the anode and the organic luminescent layer.
An organic electroluminescent device may be fabricated by a physical vapor deposition method, such as vacuum deposition, or ion plating and sputtering. The organic electroluminescent device may also be fabricated by a chemical vapor deposition using reaction gases.
Vacuum deposition in particular has been used to form the organic layer of an organic electroluminescent device. In a vacuum deposition process, an organic material is vaporized in a vacuum chamber to form an organic vapor material, and the organic vapor material is effused from an effusion cell to be deposited on a substrate.
The size of substrates has increased over time to keep pace with a trend towards large displays. To deposit an organic layer on large substrates, a deposition system has been developed in which an effusion cell in a vacuum chamber effuses an organic vapor material while moving up and down.
This deposition system may include a driving shaft that moves the effusion cell up and down. The driving shaft may be axially rotated by a driving unit. The effusion cell then vaporizes and effuses the organic material while moving up and down.
In conventional deposition systems, the driving shaft may be exposed to the organic vapor material dispersed inside the vacuum chamber. The dispersed organic vapor material may adhere to the driving shaft and prevent the effusion cell from moving smoothly. Accordingly, there is a need for a solution to prevent the dispersed organic vapor material in the vacuum chamber from adhering to the driving shaft.
In deposition systems used for large substrates, a vertical alignment system including a plurality of effusion cells installed on the same line or fixed to a shelf and moved by a moving apparatus may be used so that the organic vapor material effused from the effusion cell may be finely deposited on the substrate. The plurality of effusion cells may be moved by a moving apparatus including a driving source that is configured to allow the shelf and the moving apparatus to communicate.
However, in conventional vertical alignment systems, the driving source may be driven by preset data, and it is therefore difficult to confirm the position of a shelf that has been stopped and then moved again, such as when a shelf is stopped and then moved in the reverse direction. This may increase the danger of a collision between shelves or between shelves and other apparatus. Operator error, such as inputting bad data or causing the driving source to operate outside its normal range, may also increase the danger of a collision which may damage the effusion cells.
Therefore, there exists a need for a solution to prevent a shelves of a deposition system from colliding with another shelf or other apparatus.
A vertical alignment system in which a substrate and a mask are aligned in a standing state may be used to eliminate a warpage phenomenon of large substrates on which an effused material is deposited. Accordingly, there exists a need for a moving apparatus to precisely move effusion cells included in the vertical alignment system.